On the Fe-Cr Superlattice

In recent literatures, it has been presumed from the electric-resistance measurement, the magnetic analysis and the hardness measurement that in the alloy of the composition of atomic ratio 1:1 in Fe-Cr system, a superlattice would be formed, if the alloy is quenched from 1000° and annealed at 500° for a week followed by furnace-cooling.To ascertain this presumption an X-ray examination was performed. The specimen, which was heat-treated as described above, was X-rayed, Mn-K radiation being used to make the superlattice lines distinct.The diffraction pattern obtained shows no superlattice lines but only fundamental, where as it is predicted that the superlattice lines would be sufficiently strong to be detectable on the assumption of the superlattice of CsCl type. Therefore, it is concluded that the superlattice of a long range order is not present.